avoid import of nearby temporary with %edit

use mk**s**temp now,
and create files in subfolders.

should close gh-4731

Note that some part of the logic could now use
http://docs.python.org/2/library/tempfile.html#tempfile.NamedTemporaryFile
That will be deleted on close and avoid IPython to track it.
Merge pull request #4932 from minrk/input-lazy

always point py3compat.input to builtin_mod.input
Merge pull request #4849 from minrk/unicode-is-the-devil

Various unicode fixes (mostly on Windows)
Fix some doc formatting in pandoc checks.
Fix some formatting in widget docstrings
Remove the docscrape modules, which are part of numpydoc
More minor doc fixes.
Merge pull request #4949 from takluyver/remove-docscrape

Remove the docscrape modules, which are part of numpydoc
Merge pull request #4928 from minrk/suffixes

use importlib.machinery when available
Properly set uploaded notebook path.
Merge pull request #4927 from minrk/no-files-prefix

there shouldn't be a 'files/' prefix in FileLink[s]
Tiny comment correction
Reset file upload form after an upload.
Merge pull request #4950 from ellisonbg/file-upload

Two fixes for file upload related bugs

closes #4825
closes #4871
Merge pull request #4848 from Carreau/closes-4731

avoid import of nearby temporary with %edit
Merge pull request #4943 from takluyver/docs-shotgun-4

Docs shotgun 4
add notebook signing to nbformat
sign notebooks
add nbformat.sign.NotebookNotary
add `ipython notebook trust` subcommand